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HI-TECH WET PROCESSING(recent trends and issues)
© James ParkC. Col., FSDC., C. Text, FTI.
BACKGROUND
TEXTILES AND GARMENT PRODUCTION – MATURE INDUSTRIES
MAJOR SECTORS OF THE GLOBAL ECONOMY
FIBRE CONSUMPTION - 81 MEGATONNES INCREASING USE OF POLYESTER
EMPLOYEES – 26 MILLION WORLDWIDE
MAJOR TECHNOLOGIES - LONG ESTABLISHED
BUTCONTINUOUS DEVELOPMENT
PARTICUALRLY IN WET PROCESSING
DRAMATIC CHANGE FROM:
PRODUCTION-LED (VERTICAL) MANUFACTURING
TO
RETAIL-SPECIFIED MANUACTURING
(CONCEPT TO CONSUMER – C2C; GLOBALISATION AND GEOGRAPICAL CHANGES; LONG SUPPLY CHAINS)
CHANGE HAS REQUIRED NEW CONCEPTS:
JUST-IN-TIME (JIT) PRODUCTION
WITH
RIGHT-FIRST-TIME (RFT) PROCESSING
AND
QUICK RESPONSE (QR)TO MEET CONSUMER DEMANDS
(ESSENTIAL WITH LONG SUPPLY CHAINS)
Concept Benefits
Quick response (QR)
Reduction in stockholdingMeeting immediate demands of customer
Just-in-time (JIT)
Reduction in stockholding
Right-first-time (RFT)
Necessary to give QR and JITMajor financial savingsImproved quality and productivity
BENEFITS OF MODERN CONCEPTS
Cost Productivity Profit
Blind dyeing 100 100 100Small addition 110 80 48Large addition 135 64 -45Strip and re-dye 206 48 -375
COST COMPARISONS
In addition :- LOSS OF REVENUE AND PROFIT BY REPROCESSING RATHER THEN NEW BATCHES- EFFECT ON DESIGNED CAPACITY
•reduction in processing time•reduction in energy use•reduction in water and effluent•shortened lead times•reduced waste•better machine utilisation through production planning•reduced capital expenditure on processing equipment•reduction in dye and chemical inventory and costs
OTHER SAVINGS FROM RFT PROCESSING
Factor Monitor by lab
Control by SOP
Exht CD
Startingmaterials
Purity of water X
Substrate dyeability X
Substrate preparation X X
Dye standardisation X
Moisture content of dye X
Dyeingprocesscontrol
Weight of substrate X
Weighing and dispensing of dyes X X
Weighing and dispensing of chemicals X X
Control of liquor ratio X
Control of pH X X
Time/temperature profile X
Control of liquor flow/machine speed X X
Control of liquor circulation X
Colourcontrol
Selection of dyes X X
Behaviour of dyes in combination X X
Accuracy of laboratory dyeing X XAccuracy of transfer to bulk X X
Batch to batch reproducibilty in bulk X
Method of colour assessment X X
Determination of metamerism index X
IMPORTANT FACTORS FOR RFT PROCESSING
Saving in total dyeing cost of 30% (ranges from 24 to 36% depending on substrate type and dyeing method) for each correction eliminated through RFT dyeingReduction in dye inventory to 25% of originalReduction in dye purchases by 30% (ranges from 25 to 45%) by selecting least-cost formulations
Elimination of dyeing full to standards (10% of dye cost)Reduction in reprocessing (typically from 4 to 1.5%) Reduction in laboratory dyeing to achieve target colour (typically 8 to 2)Fabric savings due to colour sorting (10% of annual fabric purchases)
TYPICAL COST SAVINGS
NOT ALL WET PROCESSORS WORLDWIDE HAVE YET
ACHIEVED THE FULL BENEFITS OF RFT PRODUCTION
THE SUPPORT LABORATORY MUST BECOME THE NERVE CENTRE OF
THE OPERATION
Dye evaluation, selection, testing, QC
Development of application methods
Database preparation/colour matching
Substrate evaluation
Preparation of SOP
USE OF ENGINEERED COLOUR TEXTILE STANDARDS
COLOUR MEASUREMENT TECHNOLOGY:
WIDELY USED AND GIVES MAJOR BENEFITS
GREATER USE REQUIRED OF:
COLOUR SORTING ENGINEERED COLOUR STANDARDS
CONTROL TECHNOLOGY:
WIDELY USED FOR:
DISPENSING SYSTEMS
MACHINE/PROCESS CONTROL
GREATER USE REQUIRED FOR:
TOTAL MANAGEMENT TECHNIQUES
LATE STAGE PROCESSING:
- PACKAGE DYEING OF YARN- FABRIC AND GARMENT DYEING- PRINTING
OTHER AIDS TO QUICK RESPONSE
ALTERNATIVE PROCESSING ROUTES
CUT AND SEW COTTON GARMENTS
FULLY-FASHIONED COTTON GARMENTS
TEXTILE PRINTING
ACCOUNTS FOR 15% OF TEXTILE PRODUCTION
(28 BILLION SQ METRES PER YEAR – WITH 2.5% ANNUAL GROWTH)
TRADITIONAL METHODS – UP TO 20 WEEK SEQUENCE
COMPARISON OF ROUTES
Durst Konica Minolta StorkHangzhou Honghua MS Italy Xennia TechnologyLa Meccanica Reggiani Zimmer
HIGH PRODUCTION DIGITAL TEXTILE PRINTING MACHINES (2011)
Benchmarking varies between manufacturersUsually 8 colour machinesQuoted speeds of 400 to 3000 m2/hour
ZIMMER COLARIS
DIGITAL PRINTING (2011):
NOW MATCHING PRODUCTION SPEEDS OF FLAT SCREEN METHODS
APPROACHING SPEEDS OF ROTARY SCREEN METHODS
CURRENTLY ABOUT 1% OF TOTAL PRINTING PRODUCTION
FORECAST TO BE 2% OF PRINTING PRODUCTION BY 2015?
DIGITAL-PRINTING (2012) :
DIGITAL-PRINTING WITH PIGMENTS POSSIBLE(PIGMENT PRINTING MORE THAN 50% OF MARKET)
PRODUCTION OF 7,200 sq m/hour
COMPLEX CRITERIA FOR DIGITAL PRINTING INK SELECTION
DEPENDS ON : FABRIC TYPE COLORANT TYPE COMPONENT COMPATIBILITY PRINTING HEAD
TYPICAL TESTING REGIME – 18 PARAMETERS
EVALUATES: COMPATIBILITY WITH PRINTING ELEMENT SHELF LIFE INK FEED PERFORMANCE IMAGE QUALITY AND FASTNESS PROPERTIES
OTHER ISSUES AND PRESSURES ON TEXTILE CHAIN
INCREASING PRESSURE DUE TO:
OCCUPATIONAL HEALTH ENVIRONMENTAL SAFETY SAFE WORKING CONDITIONS FAIR LABOUR PRACTICES /SOCIAL JUSTICE
SUSTAINABLE TECHNOLOGY:
PROCESSES WHICH DO NOT INCUR:
EMISSION OF GREENHOUSE GASESTHE USE OF NON-RENEWABLE MATERIALSGENERATION OF WASTE
AAFA Adidas C&A Coats Liz Claiborne
Decathion Esprit Gap H&M Hanesbrands
IKEA Levis M&S Next Nike
Nordstrom S. Oliver Otto J.C. Penney Puma
REI Ann Taylor Tesco Timberland VF Corp
RESTRICTED SUBSTANCES LISTS(just a few examples)
PARTICULAR PROBLEMS WITH:
TRADITIONALLY CULTIVATED COTTON(Preparation)
POLYESTER(HT Dyeing)
(More than 80% of fibre usage)
NOT YET ENOUGH ‘ORGANIC’ COTTON
SUPERCRITICAL CO2 – WATERLESS DYEING MACHINE
ScCOO DYEING
PILOT (PACKAGE) MACHINE (1991)
FABRIC DYEING MACHINE
DYECOO SYSTEMS + NIKE
Needs : DYES + EQUIPMENT
Process :
WATERLESSSAVINGS IN ENERGY,
CHEMICALS AND TIME
NOT TOXIC
•reduction in water consumption•reduction in pollutants and volume of discharged effluent•savings in energy, including heat recovery•reduction in atmospheric pollution •minimising waste•health and safety of operatives•elimination of prohibited chemicals in consumer products
TOWARDS THE ‘GREEN’ DYEHOUSE
Development of efficient standard operating procedures (SOP) Following SOP exactly, assisted by automation Installation of machines operating at low liquor ratios Operating at minimum liquor ratio by processing full machine loads Monitoring liquor levels, assisted by automation, to avoid overfilling Improved production scheduling to avoid unnecessary machine cleaning and downtime
Replace direct heating by heat exchangers to avoid liquor volume increases Control rate of flow of cooling water through heat exchangers Return cooling water from closed-coil systems Use of water-soluble lubricants to eliminate separate scouring Combine processes or use one-bath methods whenever possible Avoid after treatment or excessive rinsing, especially overflow rinsing Allow drainage time between rinses Adopt counter-current rinsing methods in continuous processing Reuse relatively clean rinsing water for processes not requiring high-quality water Partial purification and bath reuse Total water purification and recycling Digital printing techniques
MEASURES TO REDUCE WATER CONSUMPTION
Area for consideration Factors for improvement
Water Use of low liquor ratios – machines fully loadedCombining processesWater re-useContinuous preparation, including cold pad batch methods
Effluent Treatment and water recyclingEnergy Insulation of pipes and vessels
Heat recovery from HT processes (heat exchangers)Low temperature processingUse of inverter-driven electric motors
Pollution Atmospheric control on stentersHealth and safety Colour dispensary management – individual protective
clothingSafety equipment on HT machineryElimination of hazardous or dusty chemicalsElimination of chemicals and colour in waste waterElimination of prohibited chemicals on consumer products
Dye and chemical costs Colour measurement technologyFollowing SOPs
IMPROVEMENT MEASURES
INSULATION – INSULADD COATING
Parameter Equipment improvements
Process equipment
CPB preparationLow LR/horizontal spindle package dyeing machinesRadio frequency (RF) dryingLow LR/pneumatic circulation jet dyeing machinesModern stenter installationImproved plant layoutDigital printing techniques
Control equipment
Process control, automation and robotics, managementAutomated/robotised dye and chemical weighing and dispensingColour measurement technology including digital colour communication/distance QC
Chemicals Size recoveryCaustic recovery and re-use
Water and effluent
Recovery, recycling and re-use based on in-house effluent treatment
EQUIPMENT UP-DATES
EFFLUENT TREATMENT AND WATER RECYCLING
TREATMENT ALTERNATIVES
CASE HISTORY – COTTON AND SYNTHETIC FABRICS
RAW AND TREATED EFFLUENTS
MANY DYEHOUSES TREATING EFFLUENT – RELATIVELY FEW RECYCLING TO OBTAIN MAJOR PAYBACK
SIMPLE FLOCCULATION WILL MEET CONSENT LIMITS – HIGH CHEMICAL COST
CROSSFLOW MEMBRANES PROVIDE BEST QUALITY -95% RECYCLING POSSIBLE
MEMBRANE FILTRATION WILL REDUCE COD, SUSPENDED SOLIDS AND COLOUR
RIVER WATER QUALITY IS IMPROVING WORLDWIDE WITH THE ABOVE.
CURRENT SUMMARY OF EFFLUENT TREATMENT AND RECYCLING
IN SUMMARY:
WET PROCESSING IS A HIGH-TECHNOLOGY ACTIVITY
SUCCESSFUL OPERATIONS DEPEND HEAVILY ON A MODERN SUPPORT LABORATORY
COLOUR MEASUREMENT AND CONTROL TECHNOLOGIES ARE WIDELY USED GIVING MAJOR BENEFITS AND COULD BE EXPANDED
EQUIPMENT AND PROCESSES ARE AVAILABLE TO MEET THE INCREASING DEMANDS AND PRESSURES OF THE TEXTILE CHAIN
THANK YOU FOR YOUR TIME AND KIND ATTENTION